@article{MZ_1981__178_173104,
     author = {Emilio Bujalance},
     title = {Normal {Subgroups} of {N.E.C.} {Groups.}},
     journal = {Mathematische Zeitschrift},
     pages = {331--342},
     publisher = {mathdoc},
     volume = {178},
     year = {1981},
     zbl = {0451.20047},
     url = {http://geodesic.mathdoc.fr/item/MZ_1981__178_173104/}
}